UNIVERSITY    OF    CALIFORNIA 

COLLEGE    OF    AGRICULTURE 

AGRICULTURAL    EXPERIMENT    STATION 

BERKELEY,    CALIFORNIA 

CIRCULAR  291 

June,  1925. 

BLACKHEAD  AND  OTHER  CAUSES 
OF  LOSS  OF  TURKEYS  IN  CALIFORNIA 

By  H.  W.  GRAYBILL* 


INTRODUCTION 

When  turkeys  are  reared  in  the  same  manner  as  other  fowls,  serious 
difficulties  and  even  failure  often  occur.  This  has  led  to  the  belief  that 
the  turkey,  by  nature,  is  not  well  suited  to  the  restrictions  of  domestica- 
tion and  that  it  requires  a  management  conforming  as  nearly  as 
possible  to  the  wild  state  in  order  to  thrive.  However,  there  is  much 
evidence  that  there  is  nothing  in  the  nature  of  the  turkey  which  unsuits 
it  to  domestication.  It  is  well  known  to  those  wTho  have  reared  turkeys 
by  means  of  artificial  brooding  that  they  become  tamer  than  any  of 
the  other  domestic  birds  and  do  well  under  proper  conditions  of  sani- 
tation. The  relation  of  disease  to  failures  has  not  been  generally 
understood.  It  is  evident  now  that  many  of  the  difficulties  have  been 
due  to  disease.  The  disease  which  in  general  is  of  greatest  importance — 
infectious  entero-hepatitis  or  blackhead — has  been  studied  and  the 
progress  made  in  the  control  offers  opportunities  for  overcoming 
former  difficulties.  Furthermore,  the  measures  which  have  been 
worked  out  for  the  control  of  blackhead  are  also,  fortunately,  the  most 
effective  means  known  for  controlling  other  infectious  diseases  of 
turkeys. 

In  California,  climatic  and  various  other  conditions  are  very 
favorable  to  turkey  rearing.  The  continuous  sunshine  and  the  dry, 
heated  condition  of  the  soil  during  the  dry  season,  in  sections  where 
irrigation  is  not  practiced,  are  factors  that  tend  to  purify  the  soil  and 
render  it  free  from  contamination  with  disease-producing  organisms. 
Furthermore,  the  absence  of  rain  and  storms  simplifies  rearing. 


Under  assignment  from  The  Rockefeller  Institute  for   Medical  Research. 


2  UNIVERSITY    OF    CALIFORNIA — EXPERIMENT   STATION 

The  large  unirrigated  regions  are  favorable  homes  for  the  turkey. 
On  stock  ranges  in  the  foothills  and  on  the  lower  land  bordering  the 
valleys,  there  is  an  abundance  of  insect  life  during  the  first  part  of  the 
season  and,  after  harvest,  the  grain  fields,  and  later  in  some  sections  the 
rice  fields,  offer  an  abundance  of  cheap  feed  which,  if  not  utilized  for 
turkeys,  in  a  large  measure  goes  to  waste. 


BLACKHEAD 

Prevalence. — Among  the  diseases  which  are  responsible  for  loss  of 
turkeys,  blackhead  is  probably  the  most  important.  It  has  been  found 
in  all  regions  of  the  United  States,  Canada,  the  British  Isles,  Europe, 
South  Africa  and  probably  occurs  to  some  extent  wherever  turkeys 
are  raised.  The  disease  has  assumed  such  serious  proportions  that  it 
has  been  responsible  primarily  for  turkey  raising  being  abandoned  to 
a  very  large  extent  in  certain  regions  where  formerly  it  flourished. 

Blackhead  has  long  been  known  to  occur  in  California,  and  is 
undoubtedly  responsible  for  severe  losses.  However,  if  experience 
during  the  season  of  1924  may  serve  as  a  guide,  it  is  not  so  prevalent 
as  was  supposed.  The  season,  however,  on  account  of  a  severe  drought, 
was  especially  unfavorable  for  blackhead.  Observations  made  in  some 
sections  indicate  that  the  disease  has  not  been  prevalent  to  any  great 
extent  on  well  drained  unirrigated  ranges  and  grain  fields  where  large 
bands  of  turkeys  have  been  running.  It  is  believed  that  blackhead  as 
a  serious  disease  will  be  found  to  be  localized  to  a  considerable  degree 
in  those  sections  where  the  land  is  low,  wet  or  under  irrigation. 

Birds  Susceptible  to  the  Disease. — In  addition  to  the  turkey,  the 
disease  occurs  also  occasionally  in  the  chicken,  the  pea  fowl,  the  guinea 
fowl,  and  in  pheasants,  grouse,  quail  and  possibly  other  game  birds. 
However,  game  birds  subject  to  the  disease  are  not  sufficiently  numer- 
ous, as  a  rule,  to  be  a  factor  in  the  control  of  the  disease  in  turkeys. 
None  of  the  common  wild  birds  are  known  to  be  subject  to  blackhead. 

Incidence  of  the  Disease. — The  degree  of  prevalence  of  the  disease 
in  flocks  varies  with  the  age  of  the  birds  and  the  degree  to  which  the 
soil  is  contaminated  with  blackhead.  In  young  birds  on  heavily 
infected  soil  the  number  of  birds  that  become  affected  may  approach 
or  even  reach  100  per  cent.  The  mortality  is  very  high  among  young 
birds  reaching  in  some  instances  100  per  cent.  The  proportion  of 
birds  that  become  affected  and  the  mortality  become  less  with  age. 
Chickens  are  very  resistant  to  the  disease  and  its  occurrence  among 
them  is  represented,  as  a  rule,  only  by  an  occasional  case. 


ClRC.  291]  BLACKHEAD   IN    TURKEYS   IN    CALIFORNIA  3 

Symptoms. — The  name  blackhead  is  an  unfortunate  one.  The 
head  of  the  affected  bird  never  turns  black  but  in  a  certain  proportion 
of  the  cases  takes  on  a  somewhat  bluish  color.  This  condition  occurs 
in  other  diseases  and  is  related  to  a  disturbance  of  the  circulation. 
A  period  of  about  two  weeks  elapses  between  the  beginning  of  the 
disease  and  the  time  the  affected  bird  shows  symptoms.  Birds,  espe- 
cially those  but  a  few  weeks  old,  may  die  so  suddenly  that  no  symptoms 
of  illness  have  been  noticed,  but  this  is  rather  exceptional.  The  disease 
is  most  serious  in  birds  during  the  first  months  of  life.  As  already 
indicated  resistance  increases  with  age,  especially  after  the  first  two  or 
three  months.  In  older  birds,  the  disease  is  more  chronic  and  the 
affected  bird  may  be  ill  for  some  weeks  before  it  succcumbs  or  recovers. 

The  first  change  noticed  in  a  bird  affected  with  blackhead  is  that  it 
is  a  trifle  slower  in  its  movements  and  does  not  feed  so  ambitiously. 
Later  its  movements  are  much  slower  and  it  is  found  at  times  standing 
with  the  head  drawn  in.  As  the  disease  progresses  it  stands  for  long 
intervals  or  almost  continuously  with  head  drawn  in,  eyes  closed,  and 
the  tail  and  wings  drooping.  It  may  bury  its  head  in  the  feathers  of 
the  back.  There  may  be  a  diarrhea.  The  droppings  are  stained  a 
sulfur  color.  Affected  birds  sometimes  prefer  sitting  on  the  ground  to 
standing. 

There  is  nothing  sufficiently  characteristic  about  the  symptoms  to 
make  it  possible  to  distinguish  blackhead  from  certain  other  diseases. 
A  definite  diagnosis  can  be  made  only  by  an  examination  of  the  organs 
of  birds  at  autopsy.    The  changes  to  be  found  will  be  referred  to  later. 

Medicinal  Treatment. — A  great  number  of  drugs  and  substances 
have  been  recommended  by  investigators  and  laymen  for  the  preven- 
tion and  cure  of  blackhead.  None  of  these  has  been  proved  to  be  of 
value.  As  in  the  case  of  most  other  infectious  diseases  of  animals, 
prevention  based  on  sanitation  is  more  reliable  than  curative  measures. 
The  best  that  can  be  done  for  diseased  birds  is  to  isolate  them,  give 
them  good  care,  and  feed  properly — providing  sour  milk  if  possible. 
The  results  may  be  far  from  satisfying  but  they  will  be  quite  as  much 
so  as  with  any  medicinal  treatment  and  there  will  be  no  expense  for 
drugs.  To  try,  one  after  another,  various  drugs  and  substances  recom- 
mended to  the  turkey  raiser  is  productive  of  much  harm.  Some  of 
the  substances  used  are  poisonous  or  irritating  to  the  intestinal  tract 
and  other  organs.  The  drinking  water  is  frequently  rendered  dis- 
tasteful by  the  addition  of  medicines  which  prevents  the  birds  from 
taking  a  proper  amount  of  water.  When  disease  appears  in  a  flock 
the  first  matter  of  importance  is  to  determine  definitely  its  nature  by 
an  examination  of  dead  birds.     If  the  owner  finds  himself  unable  to 


4  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

do  this,  he  should  call  a  competent  veterinarian  or  seek  the  assistance 
of  a  veterinary  laboratory  in  making  a  diagnosis.  When  the  nature 
of  the  trouble  is  discovered,  competent  advice  should  be  relied  on  for 
its  control. 

Nature  of  the  Organism  of  Blackhead. — The  "germ"  or  micro- 
organism of  blackhead  belongs  to  the  protozoa — the  lowest  forms  of 
animal  life.  Originally  the  organism  was  classed  as  an  amoeba  and 
named  Amoeba  meleagridis,  but  two  investigators,  Jowett  in  South 
Africa  and  Tyzzer  in  this  country,  have  found  evidence  which  has  led 
them  to  believe  it  belongs  to  the  flagellates,  and  the  latter  author  has 
named  it  Histomonas  meleagridis.  The  organism  has  been  well  studied 
within  the  tissues  affected  but  nothing  is  known  concerning  its  nature 
and  occurrence  elsewhere.  Fortunately,  however,  measures  of  control, 
are  not  dependent  on  this  knowledge. 

Changes  in  the  Organs. — The  main  changes  in  the  organs  in  black- 
head are  confined  to  the  ceca  and  liver,  and  these  are  the  only  organs 
as  a  rule  invaded  by  the  blackhead  parasite.  The  ceca  are  a  pair  of 
long  pouches  communicating  with  the  back  part  of  the  intestine  a  few 
inches  from  the  vent.  The  disease  of  blackhead  originates  in  these, 
one  or  both  being  affected  (fig.  1).  The  blackhead  parasite  gains 
entrance  to  the  inner  lining  (mucosa)  where  it  multiplies  very  rapidly. 
It  extends  its  invasion  well  into  the  depths  of  the  wall  of  the  cecum, 
sometimes  occupying  the  entire  thickness  of  the  wall,  causing  it  to 
become  thickened.  As  a  result  of  injury  to  the  tissues  and  a  weakening 
of  the  blood  vessels,  blood  and  fluids  may  escape  into  the  cavity  of  the 
cecum  and  there,  becoming  more  or  less  mixed  with  the  contents, 
undergo  solidification  into  a  cheesy  core.  A  core  is  not  always  present. 
According  to  the  extent  of  the  wall  invaded  by  the  organisms,  the 
thickening  may  be  general  or  localized  to  one  or  more  areas.  Enlarge- 
ment of  the  cecum,  a  thickened  wall  and  the  possible  presence  of  a 
yellowish  cheesy  core  are  the  gross  changes  to  be  noted  in  this  organ. 

In  the  wall  of  the  cecum  the  organism  gains  entrance  to  the  portal 
circulation  and  by  this  route  reaches  the  liver,  where  it  sets  up  a 
serious  disturbance.  The  liver  is  much  enlarged  and  permeated  with 
dark  red,  grayish  or  yellowish  spots  where  the  blackhead  parasite  has 
lodged  and  multiplied,  bringing  about  changes  in  the  liver  tissue 
(fig.  2).  At  times  instead  of  the  changes  occurring  as  spots,  they  may 
have  a  diffuse  nature,  giving  a  cloudy  appearance  to  considerable 
areas  of  the  liver. 

Transmission. — In  studies  on  this  phase  of  the  disease  at  the  Rocke- 
feller Institute  for  Medical  Research,  it  was  found  that  the  disease  is 


Circ.291]  BLACKHEAD    IN    TURKEYS    IN    CALIFORNIA 


J 


Fig.  1— Oeca  of  a  turkey  affected  with  blackhead.  One  ceccum  shows  a 
discolored  diseased  area  near  the  tip  and  two  near  the  middle.  The  other  shows 
only  one  located  below  the  middle. 


b  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

not  readily,  if  at  all,  transmitted  directly  from  sick  to  healthy  birds 
but  that  healthy  turkeys  and  chickens  could  render  soil,  after  a  time, 
dangerous  to  poults.*  The  investigations  finally  led  to  the  belief  that 
another  factor  might  be  necessary  to  start  the  disease.  With  this  idea 
in  mind,  attention  was  directed  to  a  small  thread  worm,  the  cecum 
worm  (Heterakis  gallinae\)  commonly  inhabiting  the  ceca  of  turkeys 
and  chickens.  It  was  found  that  by  feeding  large  numbers  of  fully 
developed  eggs  of  this  worm  to  healthy  turkeys,  blackhead  could  be 
produced.  In  blackhead  we  therefore  have  two  factors  involved  in  the 
production  of  the  disease,  one  the  blackhead  parasite,  a  microscopic 
organism  which  enters  the  tissues  and  produces  the  characteristic 
changes,  and  the  other  a  worm  which  presumably  opens  up  a  way  for 
the  blackhead  parasite  to  enter.  It  is  possible  that  there  are  other 
factors  that  may  take  the  place  of  the  cecum  worm  in  the  production 
of  blackhead,  but  none  have  been  found.  At  present,  measures  for 
the  control  of  blackhead  resolve  themselves  into  the  control  of  the 
cecum  worm. 

Life  History  of  the  Cecum  Worm. — The  cecum  worm  is  a  small 
thread  worm  about  half  an  inch  long.  The  adult  females  in  the  ceca 
deposit  microscopic  eggs  which  pass  out  in  the  droppings  in  an 
undeveloped  condition.  When  the  temperature  is  favorable,  they 
undergo  development  and  in  about  a  week  during  warm  weather,  each 
contains  a  minute  embryonic  worm.  In  this  stage,  if  taken  up  in 
food  by  a  suitable  host,  such  as  the  turkey  or  chicken,  they  pass  to  the 
intestine  where  they  hatch  and  the  embryos  are  liberated.  The  young 
worms  pass  onward  with  the  intestinal  contents,  and  finally  enter  the 
ceca  where  they  undergo  growth  and  development  to  maturity.  It  is 
the  young  microscopic  larval  worm  that  acts  as  a  factor  in  the 
production  of  blackhead. 

The  eggs  of  the  cecum  worm  are  affected  unfavorably  by  dryness, 
but  they  withstand  temperatures  of  freezing  and  below.  They  may 
remain  alive  on  the  soil  for  months  and  possibly  even  for  a  year  or  more 
although  no  doubt  a  large  proportion  perish  when  exposure  has 
continued  for  some  months. 

In  addition  to  the  turkey  and  chicken,  the  guinea  fowl,  pea  fowl, 
pheasants  and  grouse  are  hosts  of  the  cecum  worm. 

Methods  of  Control  of  Blackhead. — The  importance  of  rearing 
young  turkeys  away  from  old  ones  and  all  other  domestic  birds  and  on 
soil  as  free  as  possible  from  eggs  of  the  cecum  worm,  is  evident.    Soil 


*  Graybill,  H.  W.,  and  Theobald  Smith.     Jour.  Experimental  Medicine,  31, 
p.  647.     1920. 

t  Other  names  applied  to  this  parasite  are  H.  papillosa  and  H.  vesicularis. 


Circ.  291] 


BLACKHEAD   IN    TURKEYS   IN    CALIFORNIA 


not  previously  used  for  domestic  birds  is  satisfactory,  and  that  which 
has  been  ploughed  and  been  under  cultivation  for  a  year  during  which 
time  all  domestic  birds  have  been  excluded  may  be  regarded  as  safe. 
Wide  areas,  such  as  ranges  and  grain  fields,  may  likewise  be  regarded 
as  safe  because,  under  such  conditions,  soil  contamination  does  not 
tend  to  become  great.     From  the  time  turkeys  are  marketed  in  the 


Fig.  2. — Liver  of  turkey  affected  with  blackhead. 

winter  until  the  following  season,  as  a  rule,  few  or  no  turkeys  are 
present  on  such  areas.  This  period  favors  the  destruction  of  soil  con- 
tamination, and  in  the  case  of  grain  fields,  this  is  still  further  pro- 
moted by  ploughing  and  cultivation.  In  certain  sections  of  California 
where  dry  farming  is  practiced,  the  grain  fields  remain  unseeded  every 
other  year  but  are  ploughed  and  subjected  to  cultivation  to  keep  down 
weeds.  Such  fields  are  usually  free  from  infection  because  there  can 
be  turkeys  on  them  only  every  other  year  and  soil  contamination  is 
given  time  to  die  out. 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


KEAKING  PKACTICES  TO  CONTROL  BLACKHEAD 

Artificial  Rearing. — As  the  name  implies,  this  method  involves  the 
use  of  incubators  and  brooders.  The  popular  prejudice  that  turkeys 
cannot  be  reared  in  this  way  has  been  shown  to  be  incorrect.  Various 
investigators  working  on  blackhead  have  found  artificial  incubation 
and  brooding  applicable  to  the  turkey.  For  a  period  of  about  five  years 
birds  were  raised  in  this  way  for  experimental  work  on  blackhead  at 
the  Rockefeller  Institute  for  Medical  Research.  Here  and  there  a 
poultryman  may  be  found  who  has  been  successful.  The  Division  of 
Poultry  Husbandry  of  the  University  of  California  for  a  period  of 
some  years  has  made  observations  on  artificial  rearing  and  has  found 
it  suitable  to  the  turkey. 

The  advantage  in  artificial  brooding,  from  the  standpoint  of  disease 
control,  is  that  the  young  birds  do  not  come  into  contact  with  old 
ones  and  that  the  soil  on  which  they  are  placed,  if  clean  to  start  with,  is 
not  likely  to  become  dangerous.  Old  birds  in  addition  to  being  able 
to  contaminate  the  soil  with  blackhead  may  also  be  the  carriers  of 
various  other  diseases,  such  as  fowl  cholera,  fowl  typhoid,  and  of 
coccidia  or  other  intestinal  parasites  which  are  a  menace  to  young 
birds. 

Natural  Bearing. — With  this  method,  control  of  blackhead  is  more 
difficult  than  with  artificial  rearing.  The  principle  of  control  is  to 
subject  the  young  birds  as  little  as  possible  to  soil  contamination  result- 
ing from  the  presence  of  the  mother  birds.  It  is  therefore  important 
that  hatching  and  brooding  be  done  in  different  locations  and  that 
clean  ground  for  brooding  be  provided  each  season.  It  is  wise  to  plan 
a  year  in  advance  for  brooding  ground.  As  soon  as  practicable  the 
hens  with  their  broods  should  be  given  their  freedom  on  clean  ground. 
The  best  chance  for  success  is  where  large  areas  are  available,  for 
there  soil  contamination  is  least  likely  to  become  serious.  However,  a 
failure  to  apply  the  principles  underlying  control  may  result  in  prac- 
tices neutralizing  the  natural  advantages  of  ranges  and  fields  and 
bring  about  serious  and  unnecessary  losses.  Soil  tends  to  become 
dangerous  in  places  where  turkeys  congregate  repeatedly.  In  the  case 
of  large  bands,  the  flock  should  be  kept  on  the  move  and  feeding 
and  roosting  places  changed  frequently  to  keep  the  flock  on  soil  as 
little  contaminated  as  possible. 

The  adoption  of  the  artificial  method  of  rearing  will  go  far  in  the 
direction  of  solving  the  blackhead  problem.  When  the  natural  method 
is  pursued,  practices  based  on  principles  of  control  will  greatly 
reduce  losses. 


ClRC.  291]  BLACKHEAD   IN    TURKEYS    IX    CALIFORNIA  9 

FIELD  TRIALS  IN  THE  ARTIFICIAL   BEAEING   OF  TURKEYS   IN   THE 
SAN  JOAQUIN  VALLEY* 

Early  in  the  season  of  1924  two  cooperators  who  were  willing  to 
undertake  the  artificial  rearing  of  turkeys  were  located  in  Merced 
County,  through  the  assistance  of  Mr.  William  II.  Alison,  Jr.,  of  the 
Agriculture  Extension  Service  of  the  University.  The  purposes  of 
the  trials  made  were :  first,  to  test  the  suitability  of  the  method  in 
practice  under  farm  conditions  in  California ;  second,  to  determine 
whether  there  were  any  practical  problems  in  the  way  of  rearing 
artificially  on  a  large  scale;  and  third,  to  arouse  popular  interest  in 
this  method  of  rearing  as  a  means  of  avoiding  disease. 

Rearing  was  done  on  soil  that  had  not  been  previously  used  for 
turkeys  or  other  poultry  and  the  birds  were  not  permitted  to  come  into 
contact  with  other  turkeys  or  with  chickens. 

One  of  the  trials  was  made  in  the  vicinity  of  Planada,  California, 
in  cooperation  with  a  breeder  of  fine  birds  who  had  experienced  con- 
siderable loss  from  disease  during  previous  seasons.  Brooding  was 
conducted  in  a  well  constructed,  movable  brooder  house.  A  large 
canopy  hover,  heated  by  means  of  an  oil  burner,  was  used.  Two 
hundred  and  twenty-five  poults  were  hatched  in  two  lots  during  the 
latter  part  of  April.  Losses  occurred  from  natural  weakness,  crowding, 
chilling  and  accidents  during  the  first  three  weeks.  After  May  15 
there  was  practically  no  loss  until  September  when  thirty  were  killed 
by  dogs. 

The  birds  were  kept  more  or  less  confined  during  the  first  part  of 
the  season,  but  after  August  25  were  given  free  range. 

One  hundred  were  reared.  Had  the  loss  from  dogs  not  occurred, 
the  number  reared  would  have  been  approximately  60  per  cent. 

The  second  trial  involved  two  flocks  located  in  the  region  of 
Gustine,  California.  The  cooperator's  home  place  had  become  so  con- 
taminated with  disease  that  he  was  no  longer  able  to  raise  turkeys 
successfully.  This  made  it  necessary  to  rear  elsewhere  and  for  this 
purpose  he  leased  a  location  on  new  soil  some  miles  away. 

He  raised  two  flocks  in  separate  places,  several  miles  apart.  The 
same  type  of  brooder  was  used  for  both.  This  was  homemade  and 
rather  crude,  and  not  to  be  recommended  for  general  use.  It  consisted 
of  a  series  of  low,  covered  compartments  (2'x3')  with  the  ground 
serving  as  a  floor.  There-was  a  common,  centrally  situated  source  of 
heat  located  in  a  subterranean  fire  box  provided  with  an  oil  burner. 


*  The  writer   is  indebted   to  Dr.  J.   R.   Beach   for   advice1   and   assistance    in 
conducting  the  investigations  presented  in  this  circular. 


10 


UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 


The  heat  was  conducted  through  two  6-inch  galvanized  pipes  running 
in  opposite  directions  from  the  fire  box  and  lying  centrally  beneath 
the  soil  of  the  compartments.  The  pipes  were  two  to  three  inches 
beneath  the  surface  at  the  fire  box  and  gradually  approached  to  within 
half  an  inch  of  the  surface  at  the  outer  end  where  they  turned  upward 
and  emerged  from  the  soil.  The  heat  was  transmitted  through  the 
soil  to  the  compartments.  There  was  no  automatic  means  of  regulating 
the  heat. 

The  birds  at  all  times  were  given  a  wide  range. 


m 


Fig.  3. — Band  of  about  2000  artificially  brooded  turkeys. 

On  account  of  a  shortage  of  feed  in  Merced  County,  the  flocks 
were,  after  a  time,  moved  in  crates  by  truck  to  grain  and  rice  fields  in 
Sutter  County  in  the  region  of  Yuba  City,  where  they  remained  until 
the  close  of  the  season. 

In  the  larger  of  the  two  flocks,  3450  birds  were  hatched  during  the 
first  half  of  May.  They  were  hatched  in  two  lots  about  two  weeks 
apart,  and  consequently  were  handled  in  different  brooders.  On 
July  26,  when  the  flock  was  moved  to  Sutter  County,  it  numbered  2230. 
Most  of  the  losses  up  to  that  time  occurred  during  the  first  two  weeks. 
Only  a  few  birds  died  after  June  5.  During  a  period  of  a  few  days, 
beginning  almost  immediately  after  brooding  started,  there  was  a  loss 
of  600.  The  cause  of  this  loss  was  not  determined.  The  cooperator 
was  inclined  to  believe  it  was  due  to  impurities  in  the  buttermilk  fed, 


Circ.  291] 


BLACKHEAD   IN    TURKEYS   IN    CALIFORNIA 


11 


but  the  only  evidence  in  support  of  this  view  was  that  the  trouble 
stopped  when  the  feeding  of  buttermilk  was  discontinued.  Other  losses 
occurred  a  few  birds  at  a  time,  from  natural  weakness,  chilling, 
crowding  and  accidents. 

Feed  conditions  on  grain  stubble  to  which  the  flock  was  moved 
on  July  26  were  bad.  As  a  result,  the  condition  of  the  birds  became 
poor  and  their  vitality  so  lowered  that  exposure  to  the  first  rains  in 
October  caused  a  loss  of  about  300  by  chilling.  The  flock  was  then 
moved  to  pasture  land  on  October  5  and  on  the  20th  to  rice  stubble 
where  it  remained.  It  continued  to  do  well  with  practically  no  further 
losses.    The  number  of  birds  raised  was  1930  or  56  percent  (fig.  3). 


Fig.  4. — Band  of  about  1000  artificially  brooded  turkeys. 


The  smaller  flock,  consisting  of  1200  birds,  was  hatched  in  two 
lots,  toward  the  end  of  June  and  early  in  July.  One  hundred  and 
fifty  birds  were  lost  during  the  first  four  or  five  days  from  natural 
weakness.  On  October  16  the  flock  was  moved  to  rice  stubble  in  Sutter 
County.  It  then  numbered  1013.  Eleven  birds  at  this  time  were  lost 
by  accident.    The  number  of  birds  raised  was  996 — 83  per  cent  (fig.  4). 

The  results  of  these  three  trials  in  artificial  rearing  of  turkeys  to 
control  disease  are  gratifying.  The  inexperience  of  the  cooperators 
in  artificial  rearing  and  the  lack  of  satisfactory  equipment  in  the  case 
of  one  led  to  losses  that  are  avoidable,  so  the  percentage  of  birds  reared 
is  not  what  it  should  have  been.  But  the  results  attained  by  the 
cooperators  were  far  superior  to  those  of  previous  years.  Experience 
is  certain  to  reduce  losses. 


12  UNIVERSITY    OF    CALIFORNIA EXPERIMENT    STATION 

A  difficulty  experienced  in  rearing  large  flocks  artificially  is  that 
the  tameness  of  the  birds  makes  it  difficult  to  drive  them.  However, 
the  birds  readily  follow  a  herdsman  and  the  flocks  were  handled  suc- 
cessfully in  this  way.  The  flock  of  1200  discussed  above  was  managed 
in  this  way  with  great  ease  by  a  man  without  any  previous  experience 
with  turkeys. 


CAUSES  OF  LOSSES  IN  CALIFORNIA  OTHER  THAN  BLACKHEAD 

During  1924  an  effort  was  made  to  obtain  a  better  knowledge  of 
the  turkey  industry  in  California,  the  practices  followed,  the  causes 
of  loss  and  the  relationship  of  natural  conditions  to  disease.  A  survey 
to  ascertain  the  exact  extent  of  the  losses  was  not  found  practicable 
but  observations  and  inquiries  made  in  a  number  of  turkey  growing 
sections  indicate  that  the  annual  loss  is  not  far  from  50  per  cent. 

One  fact  brought  out  by  the  investigations  is  of  special  importance. 
It  has  been  found  that  very  serious  losses  result  from  causes  other  them 
blackhead.    In  some  sections,  these  losses  appear  to  predominate. 

Faulty  Management. — A  considerable  loss  is  due  to  causes  other 
than  disease.  Crowding  and  chilling  are  sources  of  loss  and  predatory 
animals  in  some  sections  levy  a  considerable  toll.  Insufficient  and 
improper  feeding  lead  to  losses  which  are  at  times  attributed  by  the 
turkey  raiser  to  infectious  diseases. 

In  the  matter  of  feeding,  it  is  important,  especially  in  the  case  of 
the  large  bands  of  birds  raised  on  the  ranges  and  grain  fields,  that  the 
turkey  raiser  give  attention  to  supplementing  natural  feeds  so  that 
the  turkey  may  have  a  ration  that  is  properly  balanced.  A  suitable 
grain  feed  should  supplement  that  on  the  ranges  where  insect  (protein) 
food  predominates  and  some  animal  protein  should  supplement  that  on 
the  grain  fields  where  the  carbonaceous  feeds  predominate  when  insect 
life  is  not  abundant.  Attention  to  supplementing  properly  the  feed 
that  turkeys  find  for  themselves  will  no  doubt  lead  to  better  results. 
Furthermore,  a  certain  amount  of  green  feed  is  essential  to  the  growth 
and  health  of  the  turkey.  Investigation  of  a  roup -like  disease  (nutri- 
tional roup)  of  chickens  and  turkeys  in  California  has  shown  it  to  be 
due  to  vitamin  A  deficiency  resulting  from  a  lack  of  green  feed.*  The 
long  dry  season  during  the  summer  in  California  makes  the  problem 
of  providing  green  feed  one  requiring  special  attention. 

Losses  may  occur  directly  or  indirectly  from  exposure  during  heavy 
rains  in  the  fall.     They  are  most  likely  to  occur  in  flocks  that  are  in 


*  Beach,  J.  R.     Studies  on  a  nutritional  disease  of  poultry  caused  by  vitamin 
A  deficiency.     Calif.  Sta.  Bull.  No.  378:1-24.     1924. 


ClRC.  291]  BLACKHEAD   IN    TURKEYS   IN    CALIFORNIA  13 

poor  condition.  Much  can  be  done  to  avoid  such  Josses  by  keeping 
the  birds  in  a  vigorous  condition  through  proper  feeding  and  care. 
Late  hatched  flocks  are  subject  to  Losses  even  though  in  good  condition. 

Colds  and  roup  are  not  uncommon  and  lead  to  considerable  loss. 
Much  can  be  accomplished  in  their  prevention  by  keeping  the  birds  in 
a  vigorous,  thriving  condition  through  proper  feeding  and  care. 

Infectious  Diseases. — It  is  known  that  fowl  cholera  has  in  the  past 
led  to  serious  losses  among  turkeys.  This  season  it  has  been  demon- 
strated that  fowl  typhoid  also  causes  serious  losses.  To  what  extent 
this  disease  occurs  has  not  been  determined.  It  was  diagnosed  in  three 
counties  during  the  1924  season.  In  an  outbreak  in  a  band  of  2700 
birds  investigated  by  the  writer,  there  was  a  loss  of  about  half  the 
flock.  There  is  reason  to  believe  that  improper  feeding,  exposure  and 
lack  of  proper  care  may  be  predisposing  factors  in  this  disease. 

A  Disease  from  an  Undetermined  Cause. — A  serious  loss  of  an 
undetermined  nature  occurred  in  a  flock  of  1700,  which  resulted  in 
the  death  of  1100  birds.  The  disease  appears  to  be  an  intoxication 
and  shows  some  resemblance  to  botulism.  There  was  no  history,  how- 
ever, indicating  botulism.  It  appeared  when  the  flock  was  transferred 
from  the  farmstead  to  a  camp  on  grain  stubble.  About  a  dozen 
chickens  brought  to  the  camp  for  table  use  also  contracted  the  disease 
and  died. 

The  first  symptom  noticed  is  a  weakness  of  the  legs,  which  finally 
become  paralyzed.  The  color  of  the  head  is  normal.  The  beak  is 
sometimes  held  open  and  at  times  strings  of  mucus  hang  from  the 
mouth.  The  temperature  is  normal.  The  wings  do  not  become 
paralyzed  and  the  bird  when  disturbed  moves  forward  slowly  by  flap- 
ping its  wings.  As  the  disease  progresses  the  bird  shows  somnolence, 
the  vision  is  affected,  the  neck  becomes  paralyzed,  the  head  rests  on 
the  ground,  and  the  bird  finally  goes  into  a  coma.  According  to  the 
observation  of  the  owner,  the  muscles  of  deglutition  are  paralyzed. 
The  onset  is  sudden.  Cases  of  recovery  occur.  Autopsy  examination 
showed  the  organs  including  the  brain  to  be  normal.  Aerobic  cultures 
from  heart 's  blood  and  liver  were  negative. 

Supplementing  the  feed  of  the  turkeys  to  give  them  a  better 
balanced  ration  and  supplying  some  green  feed  failed  to  have  any 
influence  on  the  disease.  No  better  results  followed  the  application  of 
sanitary  measures  and  moving  to  a  new  location  on  the  stubble.  The 
disease  appears  to  be  an  intoxication,  but  further  investigation  will  be 
required  to  determine  its  cause. 


14  UNIVERSITY    OF    CALIFORNIA EXPERIMENT   STATION 

Promiscous  Purchases  of  Stock. — Some  raisers  in  California  add 
to  their  flocks  by  purchasing  young  birds  several  months  old  and 
others  acquire  entire  flocks  in  this  manner.  Birds  are  frequently 
obtained  from  two  or  more  sources.  Unless  great  care  is  exercised  to 
obtain  birds  only  from  flocks  in  which  disease  is  not  present,  the 
practice  involves  great  danger. 

The  measures  outlined  for  the  control  of  blackhead  are  also  appli- 
cable to  other  infectious  diseases.  Correct  management  of  flocks  will 
also  assist  not  only  in  preventing  losses  from  infectious  diseases  but 
should,  in  addition,  greatly  reduce  losses  resulting  from  inadequate 
diet,  exposure  and  other  causes. 


STATION  PUBLICATIONS  AVAILABLE  FOR  FREE  DISTRIBUTION 


BULLETINS 


No. 

253.  Irrigation  and   Soil  Conditions  in  the 
Sierra  Nevada  Foothills,  California. 

261.  Melaxuma    of    the    Walnut,    "Juglans 

regia." 

262.  Citrus  Diseases  of  Florida   and  Cuha 

Compared  with  Those  of  California. 

263.  Size  Grades  for  Ripe  Olives. 

268.   Growing  and  Grafting  Olive  Seedlings. 
273.  Preliminary  Report  on  Kearney  Vine- 
yard Experimental  Drain. 

275.  The  Cultivation  of  Belladonna  in  Cali- 

fornia. 

276.  The  Pomegranate. 

277.  Sudan  Grass 

278.  Grain  Sorghums. 

279.  Irrigation  of  Rice  in  California. 

280.  Irrigation  of  Alfalfa  in  the  Sacramento 

Valley. 
283.  The  Olive  Insects  of  California. 

285.  The  Milk  Goat  in  California. 

286.  Commercial  Fertilizers. 
294.   Bean  Culture  in  California. 

304.  A  Study  of  the  Effects  of  Freezes  on 

Citrus   in   California. 
310.  Plum  Pollination. 

312.  Mariout  Barley. 

313.  Pruning  Young  Deciduous  Fruit  Trees. 
319.   Caprifigs  and  Caprification. 

324.  Storage  of  Perishable  Fruit  at  Freezing 

Temperatures. 

325.  Rice  Irrigation  Measurements  and  Ex- 

periments    in      Sacramento     Valley, 

1914-1919. 
328.  Prune  Growing  in  California. 
331.  Phylloxera-Resistant  Stocks. 

334.  Preliminary  Volume  Tables  for  Second- 

Growth  Redwood. 

335.  Cocoanut   Meal   as   a   Feed   for  Dairy 

Cows  and  Other  Livestock. 

339.  The  Relative  Cost  of  Making  Logs  from 

Small  and  Large  Timber. 

340.  Control  of  the  Pocket  Gopher  in  Cali- 

fornia. 

343.  Cheese  Pests  and  Their  Control. 

344.  Cold  Storage  as  an  Aid  to  the  Market- 

ing of  Plums. 

346.  Almond  Pollination. 

347.  The  Control  of  Red  Spiders  in  Decidu- 

ous Orchards. 

348.  Pruning  Young  Olive  Trees. 

349.  A    Study    of    Sidedraft    and    Tractor 

Hitches. 

350.  Agriculture  in  Cut-over  Redwood  Lands. 
352.   Further  Experiments  in  Plum  Pollina- 
tion. 


No. 
353. 
354. 
357. 

358. 

359. 
361. 

362. 
363. 

364. 

365. 
366. 

367. 

368. 

369. 
370. 
371. 

372. 

374. 

375. 
376. 

377. 

379. 
380. 

381. 

382. 

383. 

384. 


385. 
386. 


387. 


Bovine  Infectious  Abortion. 

Results  of  Rice  Experiments  in   1922. 

A  Self-mixing  Dusting  Machine  for 
Applying  Dry  Insecticides  and 
Fungicides. 

Black  Measles,  Water  Berries,  and 
Related  Vine  Troubles. 

Fruit  Beverage  Investigations. 

Preliminary  Yield  Tables  for  Second 
Growth  Redwood. 

Dust  and  the  Tractor  Engine. 

The  Pruning  of  Citrus  Trees  in  Cali- 
fornia. 

Fungicidal  Dusts  for  the  Control  of 
Bunt. 

Avocado   Culture   in   California. 

Turkish  Tobacco  Culture,  Curing  and 
Marketing. 

Methods  of  Harvesting  and  Irrigation 
in  Relation  to  Mouldy  Walnuts. 

Bacterial  Decomposition  of  Olives  dur- 
ing Pickling. 

Comparison  of  Woods  for  Butter  Boxes. 

Browning  of  Yellow  Newtown  Apples. 

The  Relative  Cost  of  Yarding  Small 
and  Large  Timber. 

The  Cost  of  Producing  Market  Milk  and 
Butterfat  on  246  California  Dairies. 

A  Survey  of  Orchard  Practices  in  the 
Citrus  Industry  of  Southern  Cali- 
fornia. 

Results  of  Rice  Experiments  at  Cor- 
tena,    1923. 

Sun-Drying  and  Dehydration  of  Wal- 
nuts. 

The  Cold  Storage  of  Pears. 

Walnut  Culture  in  California. 

Growth  of  Eucalyptus  in  California 
Plantations. 

Growing  and  Handling  Asparagus 
Crowns. 

Pumping  for  Drainage  in  the  San 
Joaquin  Valley,   California. 

Monilia  Blossom  Blight  (Brown  Rot) 
of  Apricot. 

A  Study  of  the  Relative  Values  of  Cer- 
tain Succulent  Feeds  and  Alfalfa  Meal 
as  Sourses  of  Vitamin  A  for  Poultry. 

Pollination  of  the  Sweet  Cherry. 

Pruning  Bearing  Deciduous  Fruit 
Trees. 

Fig  Smut. 


CIRCULARS 


No.  No. 

87.   Alfalfa.  157. 

113.   Correspondence  Courses  in  Agriculture.  160. 

117.  The    Selection    and    Cost    of    a    Small  164. 

Pumping  Plant.  165. 
127.   House  Fumigation. 

129.   The  Control  of  Citrus  Insects.  166. 

136.  Melilotus    indica    as    a    Green-Manure  167. 

Crop  for  California.  170. 
144.    Oidium  or  Powdery  Mildew  of  the  Vine. 

151.  Feeding  and  Management  of  Hogs.  173. 

152.  Some  Observations  on  the  Bulk  Hand- 

ling of  Grain  in  California.  178. 

154.  Irrigation   Practice   in   Growing   Small  179. 

Fruit  in  California. 

155.  Bovine  Tuberculosis.  184. 


Control  of  the  Pear  Scab. 
Lettuce  Growing  in  California. 
Small  Fruit  Culture  in  California. 
Fundamentals   of   Sugar   Beet   Culture 

under  California  Conditions. 
The  County  Farm  Bureau. 
Feeding  Stuffs  of  Minor  Importance. 
Fertilizing  California  Soils  for  the  1918 

Crop. 
The    Construction    of   the   Wood-Hoop 

Silo. 
The  Packing  of  Apples  in  California. 
Factors    of    Importance    in    Producing 

Milk  of  Low  Bacterial  Count. 
A  Flock  of  Sheep  on  the  Farm. 


CIRCULARS—  (Continued) 


No. 

190.  Agriculture  Clubs  in  California. 
199.   Onion  Growing  in  California. 

202.  County   Organizations   for   Rural   Fire 

Control. 

203.  Peat  as  a  Manure  Substitute. 

208.  Summary  of  the  Annual  Reports  of  the 

Farm  Advisors  of  California. 

209.  The  Function  of  the  Farm  Bureau. 

210.  Suggestions  to  the  Settler  in  California. 
212.   Salvaging  Rain-Damaged  Prunes. 

214.  Seed  Treatment  for  the  Prevention  of 

Cereal  Smuts. 

215.  Feeding  Dairy  Cows  in  California. 
217.  Methods   for  Marketing  Vegetables   in 

California. 
220.  Unfermented  Fruit  Juices. 
228.  Vineyard  Irrigation  in  Arid   Climates. 

230.  Testing   Milk,    Cream,    and   Skim   Milk 

for   Butterfat. 

231.  The  Home  Vineyard. 

232.  Harvesting    and    Handling    California 

Cherries  for  Eastern   Shipment. 

233.  Artificial  Incubation. 

234.  Winter  Injury  to  Young  Walnut  Trees 

during  1921-22. 

235.  Soil  Analysis  and  Soil  and  Plant  Inter- 

relations. 

236.  The  Common  Hawks  and  Owls  of  Cali- 

fornia   from   the    Standpoint   of   the 
Rancher. 

237.  Directions  for  the  Tanning  and  Dress- 

of  Furs. 

238.  The  Apricot  in  California. 

239.  Harvesting  and  Handling  Apricots  and 

Plums  for  Eastern  Shipment. 

240.  Harvesting    and    Handling    Pears   for 

Eastern  Shipment. 

241.  Harvesting  and  Handling  Peaches  for 

Eastern  Shipment. 

242.  Poultry   Feeding. 

243.  Marmalade  Juice  and  Jelly  Juice  from 

Citrus  Fruits. 

244.  Central  Wire  Bracing  for  Fruit  Trees. 

245.  Vine  Pruning  Systems. 

247.  Colonization  and  Rural  Development. 

248.  Some  Common  Errors  in  Vine  Pruning 

and  Their  Remedies. 

249.  Replacing  Missing  Vines. 

250.  Measurement   of    Irrigation   Water   on 

the  Farm. 

251.  Recommendations  Concerning  the  Com- 

mon    Diseases     and     Parasites     of 
Poultry  in  California. 


No. 

252. 
253. 
254. 

255. 

256. 
257. 
258. 
259. 
260. 

261. 
262. 
263. 
264. 

265. 
266. 

267. 

268. 

269. 
270. 
271. 
272. 

273. 

274. 

275. 

276. 
277. 

278. 

279. 

281. 


282. 


283. 
284. 


Supports  for  Vines. 

Vineyard  Plans. 

The  Use  of  Artificial  Light  to  Increase 
Winter  Egg  Production. 

Leguminous  Plants  as  Organic  Fertil- 
izer in   California  Agriculture. 

The  Control  of  Wild  Morning  Glory. 

The  Small-Seeded  Horse  Bean. 

Thinning  Deciduous  Fruits. 

Pear  By-products. 

A  Selected  List  of  References  Relating 
to  Irrigation  in  California. 

Sewing  Grain   Sacks. 

Cabbage  Growing  in  California. 

Tomato  Production  in  California. 

Preliminary  Essentials  to  Bovine  Tuber- 
culosis Control. 

Plant  Disease  and  Pest  Control. 

Analyzing  the  Citrus  Orchard  by  Means 
of  Simple  Tree  Records. 

The  Tendency  of  Tractors  to  Rise  in 
Front;  Causes  and  Remedies. 

Inexpensive  Lavor-saving  Poultry  Ap- 
pliances. 

An  Orchard  Brush  Burner. 

A  Farm  Septic  Tank. 

Brooding  Chicks  Artificially. 

California  Farm  Tenancy  and  Methods 
of  Leasing. 

Saving  the  Gophered  Citrus  Tree. 

Fusarium  Wilt  of  Tomato  and  its  Con- 
trol by  Means  of  Resistant  Varieties. 

Marketable  California  Decorative 
Greens. 

Home  Canning. 

Head,  Cane,  and  Cordon  Pruning  of 
Vines. 

Olive  Pickling  in  Mediterranean  Coun- 
tries. 

The  Preparation  and  Refining  of  Olive 
Oil  in  Southern  Europe. 

The  Results  of  a  Survey  to  Determine 
the  Cost  of  Producing  Beef  in  Cali- 
fornia. 

Prevention  of  Insect  Attack  on  Stored 
Grain. 

Fertilizing  Citrus  Trees  in  California. 

The  Almond  in  California. 

Oak  Fungus  in  Orchard  Trees. 


The  publications  listed  above  may  be  had  by  addressing 

College  of  Agriculture, 

University  of  California, 

Berkeley,  California. 


12w-6,'25 


